From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?J=E9r=F4me?= Pouiller Date: Sat, 19 Nov 2016 15:04:03 +0100 Subject: [Buildroot] [PATCH v2 06/15] reproducibility/linux: inhibit build-id In-Reply-To: <0274904d-a7d0-4ac1-dd28-73f920a77fa0@mind.be> References: <1479460224-6119-1-git-send-email-jezz@sysmic.org> <1479460224-6119-7-git-send-email-jezz@sysmic.org> <0274904d-a7d0-4ac1-dd28-73f920a77fa0@mind.be> Message-ID: <1479588390.8yanCXY4Bm@sagittea> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net On Saturday 19 November 2016 10:31:51 Arnout Vandecappelle wrote: > > On 18-11-16 10:10, J?r?me Pouiller wrote: > > By default, Linux kernel enable 'build-id'. 'build-id' tends to add random > > bytes in section .notes of kernel image[1]: > > Err, no, these are not random bytes, these are a sha1 of the content of the > file. If the build ID changes, it means the content has changed. > > One common way that the build ID can differ while the output files don't differ > is because of the source path that is recorded in the debug sections (which are > stripped in the end). But I think that reproducible builds when the source path > differs are very far away at this point... Oh, you are right! I didn't understood why my build-id changes while all sections was identical. In fact, in some circumstances, symbol order in debug sections is not defined. I don't know yet exactly why nor how to fix it. -- J?r?me Pouiller, Sysmic Embedded Linux specialist http://www.sysmic.fr